At present, a commonly-used display device uses two-dimensional (2D) display, which cannot present depth information of a scene directly. With the development of computer information technology and display technology, three-dimensional (3D) display technology has become a research emphasis in the display field, because it can reconstruct 3D spatial information of the scene exactly, so as to enable viewers to observe a 3D image.
Autostereoscopic display technology refers to that the viewers can observe the three-dimensional image with naked eyes, i.e., without any auxiliary tools. Among numerous three-dimensional display technologies, a grating-type autostereoscopic display technology has been widely applied due to its advantages such as a simple structure, being easy to be achieved and an excellent stereo display effect. There are mainly two types of gratings: a lens grating and a slit grating. The slit grating consists of transparent grating films with dark and bright slits arranged in an array manner, and the lens grating consists of transparent grating plates with a plurality of cylindrical lenses arranged in an array manner. The slit grating is generally used in a three-dimensional display device due to its advantages such as a simple structure, low manufacturing cost, variable grating parameters and absence of focusing problem.
At present, for example, a traditional slit grating is manufactured mostly using an electrically-operated liquid crystal element, and there also exists a light-operated grating which is manufactured using a photochromic material and controlled by switching a light source. As shown in FIG. 1, the light-operated grating in the related art includes a transparent film layer 01 and photochromic bars 02 arranged at intervals on the transparent film layer 01. The photochromic bars 02 are in a transparent state when they are not irradiated by ultraviolet light, so as to achieve the 2D display, as shown in FIG. 1(a); and the photochromic bars 02 turn to be in a light-shielding state when they are irradiated by the ultraviolet light, so as to achieve the 3D display, as shown in FIG. 1(b).
During the 3D display controlled by the light-operated grating with the above structure, the ultraviolet light for achieving the 3D display passes through the slits between the adjacent two photochromic bars and enters eyes of the viewer, which may adversely affect the viewer's healthy.